Dispensing systems are known which comprise a pump which is provided with a tube for the pressurised supply of the product and to which a dispensing head of the push-button type is fixed in order to actuate the movement of said tube over a dispensing stroke and to actuate the suction of the product.
In particular, the dispensing head may comprise a body having a well for mounting said head on the supply tube and a path for dispensing the product between said well and a discharge passage. According to an embodiment, the dispensing path is formed at least in part at the interface between an abutment provided on a recess in the dispensing head and a nozzle which is mounted around said abutment. Therefore, by pressing on the body of the dispensing head, the pump is actuated in order to dispense the product through the discharge passage as a small amount or as a continuous stream.
Throughout the world, various directives aim to regulate, control and limit the presence of substances that are potentially hazardous for human health in products, in particular cosmetic products. One of them is the European REACH (Registration, Evaluation and Authorisation of Chemicals) directive. Thus an environmental trend is driving cosmetics manufacturers to limit or even eliminate from their formulas preservatives that are often the cause of allergies or intolerances.
Cosmetic products are therefore becoming more and more fragile. In particular, it is difficult for them to withstand mechanical or thermal stress (causing for example phase separation) and contact with air (causing for example drying out or oxidation) and they can easily be contaminated by bacteria, yeasts and moulds.
To combat said contamination, formulators attempt to reinforce the intrinsic preservative activity of their products by adding ingredients having a preservative activity, such as certain essential oils, essences of orange, vitamin C, etc. that are not declared as preservatives. They also limit the free activity of water, which they attempt to keep low (AW<0.6) so that bacteria develop to little or no extent. The standard NF 29621 describes means of this type; however, formulators are rapidly approaching the limits of such a strategy.
At the same time, both with regard to the container in which the product is packaged and with regard to the dispensing head, protective bottles are appearing on the market. In particular, the bottles have to prevent microbiological contamination of the product, not only during storage but especially between two uses, and in particular by back-contamination from the discharge passage towards the inside of the container by means of the dispensing path.
In order to do this, complex and expensive dispensing heads have been proposed, the high level of antimicrobial protection of which is not always essential, in particular when the product itself has an intrinsic preservative activity.